params.c 23 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /* Helpers for initial module or kernel cmdline parsing
  3. Copyright (C) 2001 Rusty Russell.
  4. */
  5. #include <linux/kernel.h>
  6. #include <linux/string.h>
  7. #include <linux/errno.h>
  8. #include <linux/module.h>
  9. #include <linux/moduleparam.h>
  10. #include <linux/device.h>
  11. #include <linux/err.h>
  12. #include <linux/slab.h>
  13. #include <linux/ctype.h>
  14. #include <linux/security.h>
  15. #ifdef CONFIG_SYSFS
  16. /* Protects all built-in parameters, modules use their own param_lock */
  17. static DEFINE_MUTEX(param_lock);
  18. /* Use the module's mutex, or if built-in use the built-in mutex */
  19. #ifdef CONFIG_MODULES
  20. #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : &param_lock)
  21. #else
  22. #define KPARAM_MUTEX(mod) (&param_lock)
  23. #endif
  24. static inline void check_kparam_locked(struct module *mod)
  25. {
  26. BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
  27. }
  28. #else
  29. static inline void check_kparam_locked(struct module *mod)
  30. {
  31. }
  32. #endif /* !CONFIG_SYSFS */
  33. /* This just allows us to keep track of which parameters are kmalloced. */
  34. struct kmalloced_param {
  35. struct list_head list;
  36. char val[];
  37. };
  38. static LIST_HEAD(kmalloced_params);
  39. static DEFINE_SPINLOCK(kmalloced_params_lock);
  40. static void *kmalloc_parameter(unsigned int size)
  41. {
  42. struct kmalloced_param *p;
  43. p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  44. if (!p)
  45. return NULL;
  46. spin_lock(&kmalloced_params_lock);
  47. list_add(&p->list, &kmalloced_params);
  48. spin_unlock(&kmalloced_params_lock);
  49. return p->val;
  50. }
  51. /* Does nothing if parameter wasn't kmalloced above. */
  52. static void maybe_kfree_parameter(void *param)
  53. {
  54. struct kmalloced_param *p;
  55. spin_lock(&kmalloced_params_lock);
  56. list_for_each_entry(p, &kmalloced_params, list) {
  57. if (p->val == param) {
  58. list_del(&p->list);
  59. kfree(p);
  60. break;
  61. }
  62. }
  63. spin_unlock(&kmalloced_params_lock);
  64. }
  65. static char dash2underscore(char c)
  66. {
  67. if (c == '-')
  68. return '_';
  69. return c;
  70. }
  71. bool parameqn(const char *a, const char *b, size_t n)
  72. {
  73. size_t i;
  74. for (i = 0; i < n; i++) {
  75. if (dash2underscore(a[i]) != dash2underscore(b[i]))
  76. return false;
  77. }
  78. return true;
  79. }
  80. bool parameq(const char *a, const char *b)
  81. {
  82. return parameqn(a, b, strlen(a)+1);
  83. }
  84. static bool param_check_unsafe(const struct kernel_param *kp)
  85. {
  86. if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
  87. security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
  88. return false;
  89. if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
  90. pr_notice("Setting dangerous option %s - tainting kernel\n",
  91. kp->name);
  92. add_taint(TAINT_USER, LOCKDEP_STILL_OK);
  93. }
  94. return true;
  95. }
  96. static int parse_one(char *param,
  97. char *val,
  98. const char *doing,
  99. const struct kernel_param *params,
  100. unsigned num_params,
  101. s16 min_level,
  102. s16 max_level,
  103. void *arg,
  104. int (*handle_unknown)(char *param, char *val,
  105. const char *doing, void *arg))
  106. {
  107. unsigned int i;
  108. int err;
  109. /* Find parameter */
  110. for (i = 0; i < num_params; i++) {
  111. if (parameq(param, params[i].name)) {
  112. if (params[i].level < min_level
  113. || params[i].level > max_level)
  114. return 0;
  115. /* No one handled NULL, so do it here. */
  116. if (!val &&
  117. !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
  118. return -EINVAL;
  119. pr_debug("handling %s with %p\n", param,
  120. params[i].ops->set);
  121. kernel_param_lock(params[i].mod);
  122. if (param_check_unsafe(&params[i]))
  123. err = params[i].ops->set(val, &params[i]);
  124. else
  125. err = -EPERM;
  126. kernel_param_unlock(params[i].mod);
  127. return err;
  128. }
  129. }
  130. if (handle_unknown) {
  131. pr_debug("doing %s: %s='%s'\n", doing, param, val);
  132. return handle_unknown(param, val, doing, arg);
  133. }
  134. pr_debug("Unknown argument '%s'\n", param);
  135. return -ENOENT;
  136. }
  137. /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
  138. char *parse_args(const char *doing,
  139. char *args,
  140. const struct kernel_param *params,
  141. unsigned num,
  142. s16 min_level,
  143. s16 max_level,
  144. void *arg,
  145. int (*unknown)(char *param, char *val,
  146. const char *doing, void *arg))
  147. {
  148. char *param, *val, *err = NULL;
  149. /* Chew leading spaces */
  150. args = skip_spaces(args);
  151. if (*args)
  152. pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
  153. while (*args) {
  154. int ret;
  155. int irq_was_disabled;
  156. args = next_arg(args, &param, &val);
  157. /* Stop at -- */
  158. if (!val && strcmp(param, "--") == 0)
  159. return err ?: args;
  160. irq_was_disabled = irqs_disabled();
  161. ret = parse_one(param, val, doing, params, num,
  162. min_level, max_level, arg, unknown);
  163. if (irq_was_disabled && !irqs_disabled())
  164. pr_warn("%s: option '%s' enabled irq's!\n",
  165. doing, param);
  166. switch (ret) {
  167. case 0:
  168. continue;
  169. case -ENOENT:
  170. pr_err("%s: Unknown parameter `%s'\n", doing, param);
  171. break;
  172. case -ENOSPC:
  173. pr_err("%s: `%s' too large for parameter `%s'\n",
  174. doing, val ?: "", param);
  175. break;
  176. default:
  177. pr_err("%s: `%s' invalid for parameter `%s'\n",
  178. doing, val ?: "", param);
  179. break;
  180. }
  181. err = ERR_PTR(ret);
  182. }
  183. return err;
  184. }
  185. /* Lazy bastard, eh? */
  186. #define STANDARD_PARAM_DEF(name, type, format, strtolfn) \
  187. int param_set_##name(const char *val, const struct kernel_param *kp) \
  188. { \
  189. return strtolfn(val, 0, (type *)kp->arg); \
  190. } \
  191. int param_get_##name(char *buffer, const struct kernel_param *kp) \
  192. { \
  193. return scnprintf(buffer, PAGE_SIZE, format "\n", \
  194. *((type *)kp->arg)); \
  195. } \
  196. const struct kernel_param_ops param_ops_##name = { \
  197. .set = param_set_##name, \
  198. .get = param_get_##name, \
  199. }; \
  200. EXPORT_SYMBOL(param_set_##name); \
  201. EXPORT_SYMBOL(param_get_##name); \
  202. EXPORT_SYMBOL(param_ops_##name)
  203. STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
  204. STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
  205. STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
  206. STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
  207. STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
  208. STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
  209. STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
  210. STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
  211. STANDARD_PARAM_DEF(hexint, unsigned int, "%#08x", kstrtouint);
  212. int param_set_charp(const char *val, const struct kernel_param *kp)
  213. {
  214. if (strlen(val) > 1024) {
  215. pr_err("%s: string parameter too long\n", kp->name);
  216. return -ENOSPC;
  217. }
  218. maybe_kfree_parameter(*(char **)kp->arg);
  219. /* This is a hack. We can't kmalloc in early boot, and we
  220. * don't need to; this mangled commandline is preserved. */
  221. if (slab_is_available()) {
  222. *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
  223. if (!*(char **)kp->arg)
  224. return -ENOMEM;
  225. strcpy(*(char **)kp->arg, val);
  226. } else
  227. *(const char **)kp->arg = val;
  228. return 0;
  229. }
  230. EXPORT_SYMBOL(param_set_charp);
  231. int param_get_charp(char *buffer, const struct kernel_param *kp)
  232. {
  233. return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
  234. }
  235. EXPORT_SYMBOL(param_get_charp);
  236. void param_free_charp(void *arg)
  237. {
  238. maybe_kfree_parameter(*((char **)arg));
  239. }
  240. EXPORT_SYMBOL(param_free_charp);
  241. const struct kernel_param_ops param_ops_charp = {
  242. .set = param_set_charp,
  243. .get = param_get_charp,
  244. .free = param_free_charp,
  245. };
  246. EXPORT_SYMBOL(param_ops_charp);
  247. /* Actually could be a bool or an int, for historical reasons. */
  248. int param_set_bool(const char *val, const struct kernel_param *kp)
  249. {
  250. /* No equals means "set"... */
  251. if (!val) val = "1";
  252. /* One of =[yYnN01] */
  253. return strtobool(val, kp->arg);
  254. }
  255. EXPORT_SYMBOL(param_set_bool);
  256. int param_get_bool(char *buffer, const struct kernel_param *kp)
  257. {
  258. /* Y and N chosen as being relatively non-coder friendly */
  259. return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
  260. }
  261. EXPORT_SYMBOL(param_get_bool);
  262. const struct kernel_param_ops param_ops_bool = {
  263. .flags = KERNEL_PARAM_OPS_FL_NOARG,
  264. .set = param_set_bool,
  265. .get = param_get_bool,
  266. };
  267. EXPORT_SYMBOL(param_ops_bool);
  268. int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
  269. {
  270. int err = 0;
  271. bool new_value;
  272. bool orig_value = *(bool *)kp->arg;
  273. struct kernel_param dummy_kp = *kp;
  274. dummy_kp.arg = &new_value;
  275. err = param_set_bool(val, &dummy_kp);
  276. if (err)
  277. return err;
  278. /* Don't let them unset it once it's set! */
  279. if (!new_value && orig_value)
  280. return -EROFS;
  281. if (new_value)
  282. err = param_set_bool(val, kp);
  283. return err;
  284. }
  285. EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
  286. const struct kernel_param_ops param_ops_bool_enable_only = {
  287. .flags = KERNEL_PARAM_OPS_FL_NOARG,
  288. .set = param_set_bool_enable_only,
  289. .get = param_get_bool,
  290. };
  291. EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
  292. /* This one must be bool. */
  293. int param_set_invbool(const char *val, const struct kernel_param *kp)
  294. {
  295. int ret;
  296. bool boolval;
  297. struct kernel_param dummy;
  298. dummy.arg = &boolval;
  299. ret = param_set_bool(val, &dummy);
  300. if (ret == 0)
  301. *(bool *)kp->arg = !boolval;
  302. return ret;
  303. }
  304. EXPORT_SYMBOL(param_set_invbool);
  305. int param_get_invbool(char *buffer, const struct kernel_param *kp)
  306. {
  307. return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
  308. }
  309. EXPORT_SYMBOL(param_get_invbool);
  310. const struct kernel_param_ops param_ops_invbool = {
  311. .set = param_set_invbool,
  312. .get = param_get_invbool,
  313. };
  314. EXPORT_SYMBOL(param_ops_invbool);
  315. int param_set_bint(const char *val, const struct kernel_param *kp)
  316. {
  317. /* Match bool exactly, by re-using it. */
  318. struct kernel_param boolkp = *kp;
  319. bool v;
  320. int ret;
  321. boolkp.arg = &v;
  322. ret = param_set_bool(val, &boolkp);
  323. if (ret == 0)
  324. *(int *)kp->arg = v;
  325. return ret;
  326. }
  327. EXPORT_SYMBOL(param_set_bint);
  328. const struct kernel_param_ops param_ops_bint = {
  329. .flags = KERNEL_PARAM_OPS_FL_NOARG,
  330. .set = param_set_bint,
  331. .get = param_get_int,
  332. };
  333. EXPORT_SYMBOL(param_ops_bint);
  334. /* We break the rule and mangle the string. */
  335. static int param_array(struct module *mod,
  336. const char *name,
  337. const char *val,
  338. unsigned int min, unsigned int max,
  339. void *elem, int elemsize,
  340. int (*set)(const char *, const struct kernel_param *kp),
  341. s16 level,
  342. unsigned int *num)
  343. {
  344. int ret;
  345. struct kernel_param kp;
  346. char save;
  347. /* Get the name right for errors. */
  348. kp.name = name;
  349. kp.arg = elem;
  350. kp.level = level;
  351. *num = 0;
  352. /* We expect a comma-separated list of values. */
  353. do {
  354. int len;
  355. if (*num == max) {
  356. pr_err("%s: can only take %i arguments\n", name, max);
  357. return -EINVAL;
  358. }
  359. len = strcspn(val, ",");
  360. /* nul-terminate and parse */
  361. save = val[len];
  362. ((char *)val)[len] = '\0';
  363. check_kparam_locked(mod);
  364. ret = set(val, &kp);
  365. if (ret != 0)
  366. return ret;
  367. kp.arg += elemsize;
  368. val += len+1;
  369. (*num)++;
  370. } while (save == ',');
  371. if (*num < min) {
  372. pr_err("%s: needs at least %i arguments\n", name, min);
  373. return -EINVAL;
  374. }
  375. return 0;
  376. }
  377. static int param_array_set(const char *val, const struct kernel_param *kp)
  378. {
  379. const struct kparam_array *arr = kp->arr;
  380. unsigned int temp_num;
  381. return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
  382. arr->elemsize, arr->ops->set, kp->level,
  383. arr->num ?: &temp_num);
  384. }
  385. static int param_array_get(char *buffer, const struct kernel_param *kp)
  386. {
  387. int i, off, ret;
  388. const struct kparam_array *arr = kp->arr;
  389. struct kernel_param p = *kp;
  390. for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
  391. /* Replace \n with comma */
  392. if (i)
  393. buffer[off - 1] = ',';
  394. p.arg = arr->elem + arr->elemsize * i;
  395. check_kparam_locked(p.mod);
  396. ret = arr->ops->get(buffer + off, &p);
  397. if (ret < 0)
  398. return ret;
  399. off += ret;
  400. }
  401. buffer[off] = '\0';
  402. return off;
  403. }
  404. static void param_array_free(void *arg)
  405. {
  406. unsigned int i;
  407. const struct kparam_array *arr = arg;
  408. if (arr->ops->free)
  409. for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
  410. arr->ops->free(arr->elem + arr->elemsize * i);
  411. }
  412. const struct kernel_param_ops param_array_ops = {
  413. .set = param_array_set,
  414. .get = param_array_get,
  415. .free = param_array_free,
  416. };
  417. EXPORT_SYMBOL(param_array_ops);
  418. int param_set_copystring(const char *val, const struct kernel_param *kp)
  419. {
  420. const struct kparam_string *kps = kp->str;
  421. if (strlen(val)+1 > kps->maxlen) {
  422. pr_err("%s: string doesn't fit in %u chars.\n",
  423. kp->name, kps->maxlen-1);
  424. return -ENOSPC;
  425. }
  426. strcpy(kps->string, val);
  427. return 0;
  428. }
  429. EXPORT_SYMBOL(param_set_copystring);
  430. int param_get_string(char *buffer, const struct kernel_param *kp)
  431. {
  432. const struct kparam_string *kps = kp->str;
  433. return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
  434. }
  435. EXPORT_SYMBOL(param_get_string);
  436. const struct kernel_param_ops param_ops_string = {
  437. .set = param_set_copystring,
  438. .get = param_get_string,
  439. };
  440. EXPORT_SYMBOL(param_ops_string);
  441. /* sysfs output in /sys/modules/XYZ/parameters/ */
  442. #define to_module_attr(n) container_of(n, struct module_attribute, attr)
  443. #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
  444. struct param_attribute
  445. {
  446. struct module_attribute mattr;
  447. const struct kernel_param *param;
  448. };
  449. struct module_param_attrs
  450. {
  451. unsigned int num;
  452. struct attribute_group grp;
  453. struct param_attribute attrs[];
  454. };
  455. #ifdef CONFIG_SYSFS
  456. #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
  457. static ssize_t param_attr_show(struct module_attribute *mattr,
  458. struct module_kobject *mk, char *buf)
  459. {
  460. int count;
  461. struct param_attribute *attribute = to_param_attr(mattr);
  462. if (!attribute->param->ops->get)
  463. return -EPERM;
  464. kernel_param_lock(mk->mod);
  465. count = attribute->param->ops->get(buf, attribute->param);
  466. kernel_param_unlock(mk->mod);
  467. return count;
  468. }
  469. /* sysfs always hands a nul-terminated string in buf. We rely on that. */
  470. static ssize_t param_attr_store(struct module_attribute *mattr,
  471. struct module_kobject *mk,
  472. const char *buf, size_t len)
  473. {
  474. int err;
  475. struct param_attribute *attribute = to_param_attr(mattr);
  476. if (!attribute->param->ops->set)
  477. return -EPERM;
  478. kernel_param_lock(mk->mod);
  479. if (param_check_unsafe(attribute->param))
  480. err = attribute->param->ops->set(buf, attribute->param);
  481. else
  482. err = -EPERM;
  483. kernel_param_unlock(mk->mod);
  484. if (!err)
  485. return len;
  486. return err;
  487. }
  488. #endif
  489. #ifdef CONFIG_MODULES
  490. #define __modinit
  491. #else
  492. #define __modinit __init
  493. #endif
  494. #ifdef CONFIG_SYSFS
  495. void kernel_param_lock(struct module *mod)
  496. {
  497. mutex_lock(KPARAM_MUTEX(mod));
  498. }
  499. void kernel_param_unlock(struct module *mod)
  500. {
  501. mutex_unlock(KPARAM_MUTEX(mod));
  502. }
  503. EXPORT_SYMBOL(kernel_param_lock);
  504. EXPORT_SYMBOL(kernel_param_unlock);
  505. /*
  506. * add_sysfs_param - add a parameter to sysfs
  507. * @mk: struct module_kobject
  508. * @kp: the actual parameter definition to add to sysfs
  509. * @name: name of parameter
  510. *
  511. * Create a kobject if for a (per-module) parameter if mp NULL, and
  512. * create file in sysfs. Returns an error on out of memory. Always cleans up
  513. * if there's an error.
  514. */
  515. static __modinit int add_sysfs_param(struct module_kobject *mk,
  516. const struct kernel_param *kp,
  517. const char *name)
  518. {
  519. struct module_param_attrs *new_mp;
  520. struct attribute **new_attrs;
  521. unsigned int i;
  522. /* We don't bother calling this with invisible parameters. */
  523. BUG_ON(!kp->perm);
  524. if (!mk->mp) {
  525. /* First allocation. */
  526. mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
  527. if (!mk->mp)
  528. return -ENOMEM;
  529. mk->mp->grp.name = "parameters";
  530. /* NULL-terminated attribute array. */
  531. mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
  532. GFP_KERNEL);
  533. /* Caller will cleanup via free_module_param_attrs */
  534. if (!mk->mp->grp.attrs)
  535. return -ENOMEM;
  536. }
  537. /* Enlarge allocations. */
  538. new_mp = krealloc(mk->mp,
  539. sizeof(*mk->mp) +
  540. sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
  541. GFP_KERNEL);
  542. if (!new_mp)
  543. return -ENOMEM;
  544. mk->mp = new_mp;
  545. /* Extra pointer for NULL terminator */
  546. new_attrs = krealloc(mk->mp->grp.attrs,
  547. sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
  548. GFP_KERNEL);
  549. if (!new_attrs)
  550. return -ENOMEM;
  551. mk->mp->grp.attrs = new_attrs;
  552. /* Tack new one on the end. */
  553. memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
  554. sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
  555. mk->mp->attrs[mk->mp->num].param = kp;
  556. mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
  557. /* Do not allow runtime DAC changes to make param writable. */
  558. if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
  559. mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
  560. else
  561. mk->mp->attrs[mk->mp->num].mattr.store = NULL;
  562. mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
  563. mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
  564. mk->mp->num++;
  565. /* Fix up all the pointers, since krealloc can move us */
  566. for (i = 0; i < mk->mp->num; i++)
  567. mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
  568. mk->mp->grp.attrs[mk->mp->num] = NULL;
  569. return 0;
  570. }
  571. #ifdef CONFIG_MODULES
  572. static void free_module_param_attrs(struct module_kobject *mk)
  573. {
  574. if (mk->mp)
  575. kfree(mk->mp->grp.attrs);
  576. kfree(mk->mp);
  577. mk->mp = NULL;
  578. }
  579. /*
  580. * module_param_sysfs_setup - setup sysfs support for one module
  581. * @mod: module
  582. * @kparam: module parameters (array)
  583. * @num_params: number of module parameters
  584. *
  585. * Adds sysfs entries for module parameters under
  586. * /sys/module/[mod->name]/parameters/
  587. */
  588. int module_param_sysfs_setup(struct module *mod,
  589. const struct kernel_param *kparam,
  590. unsigned int num_params)
  591. {
  592. int i, err;
  593. bool params = false;
  594. for (i = 0; i < num_params; i++) {
  595. if (kparam[i].perm == 0)
  596. continue;
  597. err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
  598. if (err) {
  599. free_module_param_attrs(&mod->mkobj);
  600. return err;
  601. }
  602. params = true;
  603. }
  604. if (!params)
  605. return 0;
  606. /* Create the param group. */
  607. err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
  608. if (err)
  609. free_module_param_attrs(&mod->mkobj);
  610. return err;
  611. }
  612. /*
  613. * module_param_sysfs_remove - remove sysfs support for one module
  614. * @mod: module
  615. *
  616. * Remove sysfs entries for module parameters and the corresponding
  617. * kobject.
  618. */
  619. void module_param_sysfs_remove(struct module *mod)
  620. {
  621. if (mod->mkobj.mp) {
  622. sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
  623. /* We are positive that no one is using any param
  624. * attrs at this point. Deallocate immediately. */
  625. free_module_param_attrs(&mod->mkobj);
  626. }
  627. }
  628. #endif
  629. void destroy_params(const struct kernel_param *params, unsigned num)
  630. {
  631. unsigned int i;
  632. for (i = 0; i < num; i++)
  633. if (params[i].ops->free)
  634. params[i].ops->free(params[i].arg);
  635. }
  636. static struct module_kobject * __init locate_module_kobject(const char *name)
  637. {
  638. struct module_kobject *mk;
  639. struct kobject *kobj;
  640. int err;
  641. kobj = kset_find_obj(module_kset, name);
  642. if (kobj) {
  643. mk = to_module_kobject(kobj);
  644. } else {
  645. mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
  646. BUG_ON(!mk);
  647. mk->mod = THIS_MODULE;
  648. mk->kobj.kset = module_kset;
  649. err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
  650. "%s", name);
  651. #ifdef CONFIG_MODULES
  652. if (!err)
  653. err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
  654. #endif
  655. if (err) {
  656. kobject_put(&mk->kobj);
  657. pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
  658. name, err);
  659. return NULL;
  660. }
  661. /* So that we hold reference in both cases. */
  662. kobject_get(&mk->kobj);
  663. }
  664. return mk;
  665. }
  666. static void __init kernel_add_sysfs_param(const char *name,
  667. const struct kernel_param *kparam,
  668. unsigned int name_skip)
  669. {
  670. struct module_kobject *mk;
  671. int err;
  672. mk = locate_module_kobject(name);
  673. if (!mk)
  674. return;
  675. /* We need to remove old parameters before adding more. */
  676. if (mk->mp)
  677. sysfs_remove_group(&mk->kobj, &mk->mp->grp);
  678. /* These should not fail at boot. */
  679. err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
  680. BUG_ON(err);
  681. err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
  682. BUG_ON(err);
  683. kobject_uevent(&mk->kobj, KOBJ_ADD);
  684. kobject_put(&mk->kobj);
  685. }
  686. /*
  687. * param_sysfs_builtin - add sysfs parameters for built-in modules
  688. *
  689. * Add module_parameters to sysfs for "modules" built into the kernel.
  690. *
  691. * The "module" name (KBUILD_MODNAME) is stored before a dot, the
  692. * "parameter" name is stored behind a dot in kernel_param->name. So,
  693. * extract the "module" name for all built-in kernel_param-eters,
  694. * and for all who have the same, call kernel_add_sysfs_param.
  695. */
  696. static void __init param_sysfs_builtin(void)
  697. {
  698. const struct kernel_param *kp;
  699. unsigned int name_len;
  700. char modname[MODULE_NAME_LEN];
  701. for (kp = __start___param; kp < __stop___param; kp++) {
  702. char *dot;
  703. if (kp->perm == 0)
  704. continue;
  705. dot = strchr(kp->name, '.');
  706. if (!dot) {
  707. /* This happens for core_param() */
  708. strcpy(modname, "kernel");
  709. name_len = 0;
  710. } else {
  711. name_len = dot - kp->name + 1;
  712. strlcpy(modname, kp->name, name_len);
  713. }
  714. kernel_add_sysfs_param(modname, kp, name_len);
  715. }
  716. }
  717. ssize_t __modver_version_show(struct module_attribute *mattr,
  718. struct module_kobject *mk, char *buf)
  719. {
  720. struct module_version_attribute *vattr =
  721. container_of(mattr, struct module_version_attribute, mattr);
  722. return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
  723. }
  724. extern const struct module_version_attribute *__start___modver[];
  725. extern const struct module_version_attribute *__stop___modver[];
  726. static void __init version_sysfs_builtin(void)
  727. {
  728. const struct module_version_attribute **p;
  729. struct module_kobject *mk;
  730. int err;
  731. for (p = __start___modver; p < __stop___modver; p++) {
  732. const struct module_version_attribute *vattr = *p;
  733. mk = locate_module_kobject(vattr->module_name);
  734. if (mk) {
  735. err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
  736. WARN_ON_ONCE(err);
  737. kobject_uevent(&mk->kobj, KOBJ_ADD);
  738. kobject_put(&mk->kobj);
  739. }
  740. }
  741. }
  742. /* module-related sysfs stuff */
  743. static ssize_t module_attr_show(struct kobject *kobj,
  744. struct attribute *attr,
  745. char *buf)
  746. {
  747. struct module_attribute *attribute;
  748. struct module_kobject *mk;
  749. int ret;
  750. attribute = to_module_attr(attr);
  751. mk = to_module_kobject(kobj);
  752. if (!attribute->show)
  753. return -EIO;
  754. ret = attribute->show(attribute, mk, buf);
  755. return ret;
  756. }
  757. static ssize_t module_attr_store(struct kobject *kobj,
  758. struct attribute *attr,
  759. const char *buf, size_t len)
  760. {
  761. struct module_attribute *attribute;
  762. struct module_kobject *mk;
  763. int ret;
  764. attribute = to_module_attr(attr);
  765. mk = to_module_kobject(kobj);
  766. if (!attribute->store)
  767. return -EIO;
  768. ret = attribute->store(attribute, mk, buf, len);
  769. return ret;
  770. }
  771. static const struct sysfs_ops module_sysfs_ops = {
  772. .show = module_attr_show,
  773. .store = module_attr_store,
  774. };
  775. static int uevent_filter(struct kset *kset, struct kobject *kobj)
  776. {
  777. struct kobj_type *ktype = get_ktype(kobj);
  778. if (ktype == &module_ktype)
  779. return 1;
  780. return 0;
  781. }
  782. static const struct kset_uevent_ops module_uevent_ops = {
  783. .filter = uevent_filter,
  784. };
  785. struct kset *module_kset;
  786. int module_sysfs_initialized;
  787. static void module_kobj_release(struct kobject *kobj)
  788. {
  789. struct module_kobject *mk = to_module_kobject(kobj);
  790. complete(mk->kobj_completion);
  791. }
  792. struct kobj_type module_ktype = {
  793. .release = module_kobj_release,
  794. .sysfs_ops = &module_sysfs_ops,
  795. };
  796. /*
  797. * param_sysfs_init - wrapper for built-in params support
  798. */
  799. static int __init param_sysfs_init(void)
  800. {
  801. module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
  802. if (!module_kset) {
  803. printk(KERN_WARNING "%s (%d): error creating kset\n",
  804. __FILE__, __LINE__);
  805. return -ENOMEM;
  806. }
  807. module_sysfs_initialized = 1;
  808. version_sysfs_builtin();
  809. param_sysfs_builtin();
  810. return 0;
  811. }
  812. subsys_initcall(param_sysfs_init);
  813. #endif /* CONFIG_SYSFS */